Albert is to the left, Ernst is to the right. Ernst inherited the Dukedom and married Princess Alexandrine of Baden. Albert married Queen Victoria.
From Wikimedia. Also posted to the Revolutionary, Napoléonic, and Regency Era Album here.
This portrait was painted in 1847, but it shows earlier dress. Princess Louisa married in 1817. While very little of her dress is shown, the jewelry is spectacular.
Keywords: Döll, Louisa of Saxe-Gotha-Altenburg, Princess Louise of Saxe-Gotha-Altenburg, Duchess Louisa of Saxe-Coburg Gotha, Saxe-Gotha-Altenburg family, Saxe-Coburg Gotha family, Wettin family, Hanover family, Windsor family, Princess, Duchess, German, curly coiffure, bun, tiara, scoop neckline, sheer bertha, brooch, notched quarter length sleeves, jeweled waist band, Empire low waistline, close skirt, shoes, wrap